Light bulbs usually provide light that includes all the colors in the rainbow: violet, blue, green, yellow, orange, and red. When all of these colors are present, the light is known as xe2x80x9cwhite light.xe2x80x9d The rainbow, which is the separated colors, is known as a spectrum. Different kinds of light bulbs provide different quantities of the various colors, which means, for example, that some light bulbs provide more red light than blue light, while other light bulbs provide more green light than orange light. In addition, most light bulbs also provide light that is not visible to the naked eye, such as ultraviolet (UV) light and infrared (IR) light.
The different colors of light are known as different wavelengths of light, and range in the visible spectrum from violet or blue light having a wavelength of about 400 nm to red light having a wavelength of about 700 nm; UV light is typically between about 300 nm to 400 nm, and IR light is typically from about 700 nm to 1000 nm.
For a long time, people have wanted to select specific wavelengths and/or intensities of light for specific situations, such as for lighting a movie scene so that it looks like the middle of a bright summer day in Mexico City or a cool fall evening with a beautiful sunset in Anchorage, Ak., for diagnosing or treating disease, for measuring or analyzing the chemical or physical properties of an object, or for initiating a physical or chemical change in an object or compound or organism.
In order to obtain particular wavelengths and intensities of light, movie sets employ highly skilled and specialized lighting technicians that use very expensive light bulbs, lighting apparatus, lighting filters (such as colored xe2x80x9cgelsxe2x80x9d), and the like. The intense heat generated by the lights, however, reaches oven-like temperatures and can cook film, filters, and lighting elements. Other situations likewise employ expensive personnel and apparatus.
In some previous attempts to deal with these problems, a spectrum former, such as a prism, has been placed in front of the light bulb to separate the light beam into its respective wavelengths, then a transmissive pixelated spatial light modulator has been placed in the spectrum. A pixelated spatial light modulator is typically a square or rectangular device (although other shapes are possible) that contains a large number of tiny pixels and can be turned on or off at will. Turning a line of pixels xe2x80x9conxe2x80x9d while turning all others xe2x80x9coffxe2x80x9d permits the spatial light modulator to pick a specific color of light; more complex on/off patterns can pick more complex wavelength and intensity distributions. However, these prior attempts have been problematic because the pixelated spatial light modulators have either absorbed the undesired light or reflected it back to the original light source or spectrum former. In either case, the heat from the undesired light is not dissipated and serious problems may ensue.
Thus, there has gone unmet a need for lighting systems and luminaires that provide selected light wavelengths and intensities but that do not overheat, and that can also rapidly switch between different selected wavelengths or intensities, including highly complex groupings of wavelengths or intensities. The present invention provides these and other advantages.
The present invention provides lighting systems that provide virtually any desired color(s) and intensity(s) of light, from white light to light containing only a certain color(s) and intensity(s). The colors, or xe2x80x9cspectral output,xe2x80x9d which means a particular wavelength, band of wavelengths, or set of wavelengths, as well as the intensities, which means a xe2x80x9cwavelength dependent intensity distribution,xe2x80x9d can be combined and varied as desired. The lighting systems avoid overheating problems and can be part of other systems or stand alone units such as luminaires (for example, the high-output lighting units used to illuminate movie scenes, concert stages, and night-time construction sites). The systems can provide any desired light, such as UV light, visible light, and infrared light.
The lighting systems are a low cost, effective approach to providing carefully controlled light for a variety of purposes such as medicine, movies, theater, photography, and sports. For example, the light can be selected to substantially mimic light such as high noon in New York City, or the light necessary to diagnose or treat cancer. Additionally, the lighting can be rapidly switched from one desired scenario to another without moving major parts of the system.
The lighting systems typically comprise a spectrum former upstream from a reflective pixelated spatial light modulator (SLM). The spectrum former accepts a light beam from a light source and turns it into a spectrum, and the spectrum is then transmitted to the SLM, such as a digital micromirror device (DMD). The SLM reflects substantially all of the light impinging on the SLM into at least two different light paths that do not reflect back to the light source or the spectrum former. At least one of the light paths acts as a projection light path and transmits desired light out of the lighting system or luminaire. The other light path can act as a repository for the reflected energy, an alternate projection light path, and/or a detection light path wherein a detector measures the light reflected from the pixelated SLM to determine whether the light has the desired wavelength and intensity characteristics. Because the mirrors in the pixelated SLM can be rapidly switched back and forth between different light paths, the reflected light beam that contains the desired wavelength and intensity distribution(s) can be alternated back and forth between a projection light path and detection light path. If desired, one or more additional pixelated spatial light modulators can be provided in one or more of the light paths, to provide further enhanced specificity and preciseness in the wavelength and intensity distributions or other added benefits.
The pixelated SLM may be operably connected to a controller, which controller contains computer-implemented programming that controls the on/off pattern of the pixels in the pixelated SLM. The controller can be located in any desired location to the rest of the system. For example, the controller can be either within a housing of the luminaire or it can be located remotely, connected by a wire, cellular link or radio link to the rest of the system. If desired, the controller, which is typically a single computer but can be a plurality of linked computers, a plurality of unlinked computers, computer chips separate from a full computer or other suitable controller devices, can also contain one or more computer-implemented programs that provide specific lighting characteristics, i.e., specific desired, selected spectral outputs and wavelength dependent intensities, corresponding to known light sources such as commercial light sources, specific natural lighting situations, such as afternoon at a particular longitude, latitude, time of day and cloudiness, or a specific light for disease diagnosis or treatment, or to invoke disease treatment (for example by activating a drug injected into a tumor in an inactive form), or other particular situations.
In one aspect, the present invention provides a lighting system that provides a variable selected spectral output and a variable wavelength dependent intensity distribution. The lighting system comprising a light path that comprises: a) a spectrum former able to provide a spectrum from a light beam traveling along the light path, and b) a reflective pixelated spatial light modulator located downstream from and optically connected to the spectrum former, the reflective pixelated spatial light modulator reflecting substantially all light impinging on the reflective pixelated spatial light modulator and switchable to reflect light from the light beam between at least first and second reflected light paths that do not reflect back to the spectrum former. The reflective pixelated spatial light modulator can be a digital micromirror device. The reflective pixelated spatial light modulator is operably connected to at least one controller containing computer-implemented programming that controls an on/off pattern of pixels in the reflective pixelated spatial light modulator to reflect a desired segment of light in the spectrum to the first reflected light path and reflect substantially all other light in the spectrum impinging on the reflective pixelated spatial light modulator to at least one of the second reflected light path and another reflected light path that does not reflect back to the spectrum former, the desired segment of light consisting essentially of a desired selected spectral output and a desired wavelength dependent intensity distribution.
In some embodiments, the system further comprises a light source located upstream from the spectrum former, and the spectrum former comprises at least one of a prism and a diffraction grating, which can be a reflective diffraction grating, transmission diffraction grating, variable wavelength optical filter, or a mosaic optical filter. The system may or may not comprise, between the spectrum former and the reflective pixelated spatial light modulator, an enhancing optical element that provides a substantially enhanced image of the spectrum from the spectrum former to the reflective pixelated spatial light modulator. The reflective pixelated spatial light modulator can be a first reflective pixelated spatial light modulator, and the desired segment of light can be directed to a second reflective pixelated spatial light modulator operably connected to the same controller or another controller containing computer-implemented programming that controls an on/off pattern of pixels in the second reflective pixelated spatial light modulator to reflect the desired segment or other segment of light in one direction and reflect other light in the spectrum in at least one other direction. The system can further comprise an optical projection device located downstream from the first reflective pixelated spatial light modulator to project light out of the lighting system as a directed light beam.
The desired segment of light can be selected to substantially mimic a spectral output and a wavelength dependent intensity distribution of at least one of a known lamp, a cathode ray tube image display device, a light emissive image display device, firelight, candlelight, sunlight or other desired natural ambient lighting scenarios, the output energy for disease treatment, photodynamic therapy, or disease diagnosis, or to enhance contrast for detection or discrimination of a desired object in a scene.
In another aspect, the present invention provides a stand alone luminaire sized to project light onto a scene and having a variable selected spectral output and wavelength dependent intensity distribution. The luminaire can comprise a) a high output light source, b) a spectrum former optically connected to and downstream from the light source to provide a spectrum from a light beam emitted from the light source, c) an enhancing optical element connected to and downstream from the spectrum former that provides an enhanced image of the spectrum; d) a reflective pixelated spatial light modulator located downstream from and optically connected to the spectrum former, the reflective pixelated spatial light modulator reflecting substantially all light impinging on the reflective pixelated spatial light modulator and switchable between at least first and second reflected light paths that do not reflect back to the spectrum former, wherein the reflective pixelated spatial light modulator can be operably connected to at least one controller containing computer-implemented programming that controls an on/off pattern of pixels in the reflective pixelated spatial light modulator to reflect a desired segment of light in the spectrum in first reflected light path and reflect other light in the spectrum to at least one of the second reflected light path and another reflected light path that does not reflect back to the spectrum former, the desired segment of light consisting essentially of a desired selected spectral output and a desired wavelength dependent intensity distribution; and, e) a projection system optically connected to and downstream from the reflective pixelated spatial light modulator in the first direction, wherein the projection system projects the desired segment as a directed light beam to illuminate the scene.
The luminaire can further comprise a detector optically connected to and downstream from the reflective pixelated spatial light modulator, the detector also operably connected to a controller containing computer-implemented programming able to determine from the detector whether the desired segment contains a desired selected spectral output and a desired wavelength dependent intensity distribution, and adjust the on/off pattern of pixels in the reflective pixelated spatial light modulator to improve the correspondence between the desired segment and the desired selected spectral output and the desired wavelength dependent intensity distribution. The luminaire can also comprise a heat removal element operably connected to the light source to remove undesired energy emitted from the light source toward at least one of the reflective pixelated spatial light modulator, the enhancing optical element, and the spectrum former. The luminaires and lighting systems, as well as methods, kits, and the like related to them, can further comprise various elements that may be specifically discussed for only one or the other (for example, the detector of the luminaire is also suitable for use with the lighting system).
The heat removal element can be located between the spectrum former and the first reflective spatial light modulator, between the lamp and the spectrum former, or elsewhere as desired. The heat removal element can comprise a dichroic mirror. The dichroic mirror can transmits desired wavelengths and reflects undesired wavelengths, or vice-versa. The undesired energy can be directed to an energy absorbing surface and thermally conducted to a radiator. The heat removal element can be an optical cell containing a liquid that absorbs undesired wavelengths and transmits desired wavelengths. The liquid can be substantially water and can flow through the optical cell via an inlet port and outlet port in a recirculating path between the optical cell and a reservoir. The recirculating path and the reservoir can comprise a cooling device, which can be a refrigeration unit, a thermo-electric cooler, or a heat exchanger.
The luminaire further can comprise a spectral recombiner optically connected to and located downstream from the pixelated spatial light modulator, which can comprise a prism, a Lambertian optical diffusing element, a directional light diffuser such as a holographic optical diffusing element, a lenslet array, or a rectangular light pipe. In one embodiment, the spectral recombiner can comprise an operable combination of a light pipe and at least one of a lenslet array and a holographic optical diffusing element. The detector can be located in the at least one other direction, and can comprise at least one of a CCD, a CID, a CMOS, and a photodiode array. The high output light source, the spectrum former, the enhancing optical element that provides an enhanced image, the reflective pixelated spatial light modulator, and the projection system, can all be located in a single housing, or fewer or more elements can be located in a single housing.
In a further aspect, the present invention provides methods of lighting a scene comprising: a) directing a light beam along a light path and through a spectrum former to provide a spectrum from the light beam traveling; b) reflecting the spectrum off a reflective pixelated spatial light modulator that can be operably connected to at least one controller containing computer-implemented programming that controls an on/off pattern of pixels in the reflective pixelated spatial light modulator, wherein the reflecting can comprise reflecting a desired segment of light in the spectrum in a first reflected light path that can be not back to the spectrum former and reflecting substantially all other light in the spectrum impinging on the reflective pixelated spatial light modulator in at least one second reflected light path that can be not back to the spectrum former, to provide a modified light beam consisting essentially of a selected spectral output and a selected wavelength dependent intensity distribution.
The methods further can comprise emitting the light beam from a light source located in a same housing as and upstream from the spectrum former. The methods further can comprise switching the modified light beam between the first reflected light path and the second reflected light path. The methods further can comprise passing the light beam by an enhancing optical element between the spectrum former and the reflective pixelated spatial light modulator to provide a substantially enhanced image of the spectrum from the spectrum former to the reflective pixelated spatial light modulator. The reflective pixelated spatial light modulator can be a first reflective pixelated spatial light modulator, and the methods further can comprise reflecting the modified light beam off a second reflective pixelated spatial light modulator operably connected to at least one controller containing computer-implemented programming that controls an on/off pattern of pixels in the second reflective pixelated spatial light modulator to reflect the desired segment of light in one direction and reflect other light in the spectrum in at least one other direction.
The methods further can comprise passing the modified light beam by an optical projection device located downstream from at least one of the first reflective pixelated spatial light modulator and the second reflective pixelated spatial light modulator to project light as a directed light beam.
The methods of lighting a scene can also comprise: a) directing a light beam along a light path and through a spectrum former to provide a spectrum from the light beam traveling; and, b) passing the spectrum via a pixelated spatial light modulator located downstream from and optically connected to the spectrum former, the pixelated spatial light modulator operably connected to at least one controller containing computer-implemented programming that controls an on/off pattern of pixels in the pixelated spatial light modulator, wherein the on/off pattern can be set to pass a desired segment of light in the spectrum in one direction and interrupt other light in the spectrum impinging on the pixelated spatial light modulator, to provide a modified light beam consisting essentially of a selected spectral output and a selected wavelength dependent intensity distribution, and wherein the methods does not comprise passing the spectrum by an enhancing optical element between the spectrum former and the pixelated spatial light modulator that provides an enhanced image of the spectrum from the spectrum former to the pixelated spatial light modulator.
In still other aspects, the present invention provides methods of emitting modified light consisting essentially of a desired selected spectral output and a desired wavelength dependent intensity distribution from a stand alone luminaire. The methods can comprise: a) emitting light from a high output light source located in a housing of the luminaire; b) passing the light by a spectrum former optically connected to and downstream from the light source to provide a spectrum from a light beam emitted from the light source; c) passing the spectrum by an enhancing optical element connected to and downstream from the spectrum former to provide an enhanced image of the spectrum; d) reflecting the spectrum off a reflective pixelated spatial light modulator that can be operably connected to at least one controller containing computer-implemented programming that controls an on/off pattern of pixels in the reflective pixelated spatial light modulator, wherein the reflecting can comprise reflecting a desired segment of light in the spectrum in a first reflected light path that can be not back to the spectrum former and reflecting substantially all other light in the spectrum impinging on the reflective pixelated spatial light modulator in at least one second reflected light path that can be not back to the spectrum former, to provide a modified light beam consisting essentially of a selected spectral output and a selected wavelength dependent intensity distribution; and, e) passing the modified light beam by a projection system optically connected to and downstream from the reflective pixelated spatial light modulator in the first direction, wherein the projection system projects the modified light beam from the luminaire as a directed light beam.
The methods can further comprise reflecting the desired segment of light to a detector optically connected to and downstream from the reflective pixelated spatial light modulator, the detector located in the second reflected light path or otherwise as desired and operably connected to the controller, wherein the controller contains computer-implemented programming able to determine from the detector whether the desired segment contains the desired selected spectral output and the desired wavelength dependent intensity distribution, and therefrom determining whether the first segment contains the desired selected spectral output and the desired wavelength dependent intensity distribution. The methods can comprise adjusting the on/off pattern of pixels in the reflective pixelated spatial light modulator to improve the correspondence between the desired segment and the desired selected spectral output and the desired wavelength dependent intensity distribution.
The methods can also comprise removing undesired energy emitted from the light source toward at least one of the reflective pixelated spatial light modulator, the enhancing optical element, and the spectrum former, the removing effected via a heat removal element operably connected to the light source. The methods further can comprise a spectral recombiner optically connected to and located downstream from the reflective pixelated spatial light modulator.
These and other aspects, features and embodiments are set forth within this application, including the following Detailed Description and attached drawings. The present invention comprises a variety of aspects, features, and embodiments; such multiple aspects, features and embodiments can be combined and permuted in any desired manner. In addition, various references are set forth herein, including in the Cross-Reference To Related Applications, that discuss certain apparatus, systems, methods, or other information; all such references are incorporated herein by reference in their entirety and for all their teachings and disclosures, regardless of where the references may appear in this application.